1. Field of the Invention
The present invention relates to a lens apparatus, and more particularly, to a lens apparatus including a flange back distance adjusting mechanism.
2. Description of the Related Art
Up to now, as a lens apparatus which is used in a television camera for broadcasting, business use, or the like, there has been known a lens apparatus including a mechanism which automatically or manually adjusts a distance (that is, a flange back distance) from a flange surface (attachment surface) of a rear end of a lens holding frame to an imaging surface (a light receiving surface of an image pickup element of the camera) when the lens apparatus is fitted to a camera main body.
For example, a lens apparatus described in Japanese Patent Application Laid-Open No. 09-197261 is provided with a special switch for making the transition to a flange back distance adjustment mode, and when this special switch is pressed, the flange back distance adjustment is automatically performed.
Incidentally, a lens operation when the flange back distance adjustment is carried out is different from that at the time of normal photography, and hence the normal photographing operation cannot be performed when the lens apparatus is in the flange back distance adjustment mode. Meanwhile, if the lens apparatus is operated in the same manner as at the time of the normal photography without knowing that the lens apparatus is in the flange back distance adjustment mode, the flange back distance adjustment is not properly carried out. Therefore, it is convenient if a photographer (user) can know whether or not the lens apparatus is in the flange back distance adjustment mode.
The lens apparatus described in Japanese Patent Application Laid-Open No. 09-197261 is provided with a display part which indicates an operation state of the flange back distance adjustment. When the adjustment operation of the flange back distance is being performed, the display part is blinked on and off, to thereby warn a photographer that the normal operation is impossible. At the timing at which the adjustment operation is finished, the display part is lighted, to thereby indicate that the flange back distance has been adjusted.